SharePoint 2013 upload speed to list is very slow

I am having speed issues when pasting data to a list in SharePoint 2013. I have IE 9 and Microsoft Office 2010. When copying data from Excel to SharePoint in Datasheet view (or quick edit view as it is now), it takes enormous time to create a new row in the list. In other words, if I change data in already existing rows, the speed is fine. If I create new rows, the data is firstly copied in a good speed but then SharePoint verifies something row by row and this takes a lot of time. I can see a circling thing on the left.

Does anyone have the same issue and do you know how we could speed up SharePoint? The current speed is 70 rows created per minute. We have lists from 1500 to 80000 lines. Thank you.